Brownish Red particles during SLAM - Is this dead mustard algae

Karl103

Bronze Supporter
Aug 18, 2018
48
Rolesville, NC
Question about some material I picked up with my vaccuum.

So I did SLAM 2 weeks ago - all went well. Then this week started noticing brownish "dust" at the bottom of the pool with some cloudiness. I did an OCLT and it was borderline with 0.8 chlorine loss. So I just decided to SLAM and then get the FC up to mustard algae levels.

This morning after 18 hours of SLAM at mustard algae level FC - saw some brownish yellow particles at bottom of pool (figured it was dead algae) Ran my robot vaccuum and when I cleaned out the robot filter noted a large amount of reddish brown colored debris - more red than brown. Bottom of the pool now looks great and water is clear.

My question is - is this what dead mustard algae looks like ?

Last testing numbers

FC = 35
CYA = 60

Thanks,

Karl
 

Karl103

Bronze Supporter
Aug 18, 2018
48
Rolesville, NC
I’ll get a picture next time I vacuum. I do not have high iron in fill water that I am aware of - not well water. No stone around to cause. Only seemed to occur during mustard algae SLAM. Unless what I thought was mustard algae was iron. Had that brown dust appearance when I started the slam and now less and less since SLAM began
 

Karl103

Bronze Supporter
Aug 18, 2018
48
Rolesville, NC
I’ll get a picture next time I vacuum. I do not have high iron in fill water that I am aware of - not well water. No stone around to cause. Only seemed to occur during mustard algae SLAM. Unless what I thought was mustard algae was iron. Had that brown dust appearance when I started the slam and now less and less since SLAM began
Yes - that's my pool. There is tect
That isn't your pool in the picture? That looks like stone on the deck and the water feature. Is it textured concrete?
Yes - that's my pool - there is textured concrete I guess I misunderstood you - I thought that you meant red colored concrete. Its not red sandstone I do not think. Do you think the runoff from this concrete can cause an increase in iron ?